修复 person-detail 按钮文字未居中

原因：微信 <button> 自带 min-height 88rpx 和固有 line-height，
会顶歪自定义高度。改用 <view> + flex 居中。

- 5 个 button 改为 view（保留 class/bindtap/data-id）
- action-btn / edit-btn / delete-btn 改 flex 居中
- add-btn 加 inline-flex 居中

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

pages/person-detail/person-detail.wxml

@@ -12,8 +12,8 @@
     <text wx:if="{{person.remark}}" class="person-remark">{{person.remark}}</text>
 
     <view class="actions">
-      <button class="action-btn" bindtap="onEditPerson">编辑</button>
-      <button class="action-btn danger" bindtap="onDeletePerson">删除</button>
+      <view class="action-btn" bindtap="onEditPerson">编辑</view>
+      <view class="action-btn danger" bindtap="onDeletePerson">删除</view>
     </view>
   </view>
 
@@ -21,7 +21,7 @@
   <view class="section">
     <view class="section-header">
       <text class="section-title">纪念日列表 ({{anniversaries.length}})</text>
-      <button class="add-btn" bindtap="onAddAnniversary">+ 添加纪念日</button>
+      <view class="add-btn" bindtap="onAddAnniversary">+ 添加纪念日</view>
     </view>
 
     <view wx:if="{{anniversaries.length === 0}}" class="empty-state">
@@ -54,8 +54,8 @@
       <view wx:if="{{item.remark}}" class="anniversary-remark">{{item.remark}}</view>
 
       <view class="anniversary-actions">
-        <button class="edit-btn" bindtap="onEditAnniversary" data-id="{{item.id}}">编辑</button>
-        <button class="delete-btn" bindtap="onDeleteAnniversary" data-id="{{item.id}}">删除</button>
+        <view class="edit-btn" bindtap="onEditAnniversary" data-id="{{item.id}}">编辑</view>
+        <view class="delete-btn" bindtap="onDeleteAnniversary" data-id="{{item.id}}">删除</view>
       </view>
     </view>
   </view>